Technical information supporting the 2020 climate (fire

Technical information supporting the 2020

climate (fire danger weather)

Environmental Trend and Condition Report

Card

Department for Environment and Water

November, 2020

DEW Technical note 2020/32

DEW Technical note 2020/32 i

Department for Environment and Water

Government of South Australia

October 2020

81-95 Waymouth St, ADELAIDE SA 5000

Telephone +61 (8) 8463 6946

Facsimile +61 (8) 8463 6999

ABN 36702093234

www.environment.sa.gov.au

Disclaimer

The Department for Environment and Water and its employees do not warrant or make any representation

regarding the use, or results of the use, of the information contained herein as regards to its correctness, accuracy,

reliability, currency or otherwise. The Department for Environment and Water and its employees expressly

disclaims all liability or responsibility to any person using the information or advice. Information contained in this

document is correct at the time of writing.

With the exception of the Piping Shrike emblem, other material or devices protected by Aboriginal rights or a

trademark, and subject to review by the Government of South Australia at all times, the content of this document

is licensed under the Creative Commons Attribution 4.0 Licence. All other rights are reserved.

© Crown in right of the State of South Australia, through the Department for Environment and Water 2020

ISBN 978-1-925964-93-6

Preferred way to cite this publication

Department for Environment and Water (2020). Technical information supporting the 2020 climate (fire danger

weather) Environmental Trend and Condition Report Card. DEW Technical note 2020/32, Government of South

Australia, Department for Environment and Water, Adelaide.

Download this document at https://data.environment.sa.gov.au

http://www.environment.sa.gov.au/

https://data.environment.sa.gov.au/

DEW Technical note 2020/32 ii

Acknowledgements

This document was prepared by Graham Green (DEW). Brett Lauchlin (CFS) and Mike Wouters (DEW) provided

technical review of this report. Improvements were made to this report and associated report card based on

reviews by Jason Vanlaarhoven, Fi Taylor and Michelle Bald.

DEW Technical note 2020/32 iii

Contents

Acknowledgements ii

Summary 1

1 Introduction 2

1.1 Environmental trend and condition reporting in SA 2

1.2 Purpose and benefits of SA’s trend and condition report cards 2

2 Methods 3

2.1 Indicators 3

2.2 Data sources and collection 4

2.3 Analysis 4

2.3.1 Trend 4

2.3.2 Condition 4

2.3.3 Reliability 5

3 Results 7

3.1 Trends in annual accumulated FFDI 7

3.2 December accumulated FFDI 1950 – 2019 8

3.3 Analysis of Trend, Condition and Information Reliability 8

3.3.1 Trend 8

3.3.2 Condition 9

3.3.3 Reliability 9

4 Discussion 10

4.1 Trend 10

4.2 Condition 10

5 References 11

DEW Technical note 2020/32 iv

List of figures

Figure 3.1. Trend in annual accumulated FFDI per decade 1978 – 2019 7

Figure 3.2. December accumulated FFDI for the years 1950 – 2019 8

List of tables

Table 2.1. Trend definitions. 4

Table 2.2. Definition of condition classes 5

Table 2.3. Guides for applying information currency 5

Table 2.4. Guides for applying information applicability 5

Table 2.5. Guides for applying spatial representation of information (sampling design) 6

Table 2.6. Guides for applying accuracy information 6

Table 3.1. Information reliability scores for FFDI 9

DEW Technical note 2020/32 1

Summary

This document describes the indicators, data sources, analysis methods and results used to develop this report

and the associated report card. The reliability of data sources for their use in this context are also described.


1 Introduction

1.1 Environmental trend and condition reporting in SA

The Minister for Environment and Water under the Landscape South Australia Act 2019 is required to 'monitor,

evaluate and audit the state and condition of the State's natural resources, coasts and seas; and to report on the state

and condition of the State's natural resources, coasts and seas' (9(1(a-b)). Environmental trend and condition report

cards are produced as the primary means for the Minister to undertake this reporting. The Environment Protection

Act 1993, also requires the development of a State of the Environment Report (SOE), and states that the SOE must:

Include an assessment of the condition of the major environmental resources of South Australia 112(3(a))

Include a specific assessment of the state of the River Murray, especially taking into account the Objectives

for a Healthy River Murray under the River Murray Act 2003 112(3(ab))

Identify significant trends in environmental quality based on an analysis of indicators of environmental quality

112(3(b)).

1.2 Purpose and benefits of SA’s trend and condition report cards

South Australia’s environmental trend and condition report cards focus on the State’s priority environmental

assets and the pressures that impact on these assets. The report cards present information on trend, condition and

information reliability in a succinct visual summary.

The full suite of report cards capture patterns in trend and condition at a state scale, and give insight to changes

in a particular asset over time. They also highlight gaps in our knowledge on priority assets that prevents us from

assessing trend and condition, and might impede our ability to make evidence based decisions.

Both the trend and condition are considered important, however, the report cards give particular emphasis to

trend. Trend shows how the environment has responded to past drivers, decisions, and actions, and is what we

seek to influence through future decisions and actions.

The recognised benefits of trend and condition report cards include to:

Provide insight into our environment by tracking its change over time

Interpret complex information in a simple and accessible format

Provide a transparent and open evidence base for decision-making

Highlight those knowledge gaps that will impede South Australia’s ability to make decisions

Drive alignment of environmental reporting, ensuring we ‘do once, use many times’

Identify opportunities for further investment and on-ground action.

The initial development of the South Australian environmental trend and condition report cards was guided by the

NRM State and Condition Reporting Framework (Government of South Australia 2012). The format, design and

accessibly of the report cards has been modified and improved with each release. Environmental Trend and

Condition Report Cards are designed to align with and inform both South Australian and National State of the

Environment Reporting.

https://data.environment.sa.gov.au/Trend-and-condition-reports/Pages/default.aspx

https://data.environment.sa.gov.au/Trend-and-condition-reports/Pages/default.aspx


2 Methods

2.1 Indicators

The indicators considered in the Fire Danger Weather report card are:

for the trend assessment, the annual Accumulated Forest Fire Danger Index (FFDI), and

for the condition assessment, the December 1950 – 2019 FFDI for December. The extremely high FFDI

for December 2019 is provided as a marker of the recent high fire danger weather conditions.

Fire danger in forested landscapes of south eastern Australia is assessed using McArthur’s FFDI (Noble et al. 1980),

which is defined as:

The FFDI is determined from the sum of the daily FFDI at 3.00pm over the stated reporting period. The annual

FFDI is the sum of daily FFDI over each year. The December FFDI is the sum of daily FFDI over the 31 days of

each December.

As an indicator of fire weather danger, the FFDI has the benefits of combining a number of weather variables that

affect the likelihood, intensity and spread of fires. The variables incorporated within the FFDI formula are:

temperature (T), wind speed (v), relative humidity (RH) and a ‘drought factor’ (DF) that is based on a soil dryness

index that represents the influence of recent temperatures and rainfall on fuel dryness.

As the FFDI changes from minute-to-minute, it does not provide a good indicator of the change in conditions over

time. The benefit of FFDI as an indicator is that it integrates daily variability over a time period (month, season,

year), which should result in a value that is relatively consistent over time and will show a rising or falling trend if

there is a sustained change in one or more of the factors that comprise the FFDI formula.

The Bureau of Meteorology (BOM) database of FFDI from 1950 to present day currently provides the only

continuous long-term record available of an indicator of weather conditions that affect fire danger. However,

FFDI is not an ideal measure of the changes in fire danger weather. In particular, it does not provide any indicator

of changes to short-term weather conditions associated with the arrival of frontal systems that are associated with

times of particularly high fire risk in many regions of SA. Further, the FFDI provides only an indication of the FFDI

at a particular time of day (3.00pm) and so will not capture any systematic changes over time to weather

conditions at other times of day. With these limitations it is important to note that FFDI is not used in

environmental trend and condition report cards to report on absolute risk of bushfire, but only as an indicator of

long term trend in the combination of dry, windy and hot conditions that may increase the occurrence of

bushfires. The intention here is to provide an indication of how changes in climate are affecting changes in the

occurrence of more dangerous fire weather conditions. Accumulated FFDI is regularly reported on by the BOM to

indicate trends in fire weather conditions (BOM 2019a, BOM 2019b, BOM 2020).

A new Australian Fire Danger Rating System is in development, which will combine the latest science, experience

and data to strengthen the ability of fire authorities to accurately communicate bushfire danger to the community.

This new system may provide an alternative indicator of fire danger weather conditions that could be applied in

future updates of the environmental trend and condition report cards.


2.2 Data sources and collection

Information on the spatial and temporal variation in accumulated annual and December FFDI from 1950 to 2019

was obtained directly from the Bureau of Meteorology (BoM), which is the lead agency for weather monitoring

nationally and maintains records of the daily FFDI for locations across Australia.

2.3 Analysis

2.3.1 Trend

Information for the trend in annual accumulated FFDI is provided as an interpolated colour-coded map, showing a

state-wide interpolation of the trend in annual FFDI, represented by the change per decade in total accumulated

FFDI units per year.

The trend classifications used in DEW’s Trend and Condition Report Cards are given in Table 2.1.

Table 2.1. Trend definitions.

Trend Trend Definition

Getting better Over a scale relevant to tracking change in the indicator it is improving in status with good

confidence

Stable Over a scale relevant to tracking change in the indicator it is neither improving nor declining in

status

Getting worse Over a scale relevant to tracking change in the indicator it is declining in status with good

confidence

Unknown Data are not available, or are not available at relevant temporal scales, to determine any trend in

the status of this resource

Not applicable This indicator of the natural resource does not lend itself to being classified into one of the above

trend classes

2.3.2 Condition

Data on the December accumulated FFDI for the years from 1950 to 2019 was provided by BOM as a text file with

a single December accumulated FFDI figure for each year. This dataset was used to construct a simple column

graph, illustrating the total December accumulated FFDI from 1950-2019.

The condition classifications used in DEW’s Environmental Trend and Condition Report Cards are given in

Table 2.2.


Table 2.1. Definition of condition classes

Condition Condition definition

Very good The natural resource is in a state that meets all environmental, economic and social expectations,

based on this indicator. Thus, desirable function can be expected for all processes/services expected of

this resource, now and into the future, even during times of stress (e.g. prolonged drought).

Good The natural resource is in a state that meets most environmental, economic and social expectations,

based on this indicator. Thus, desirable function can be expected for only some processes/services

expected of this resource, now and into the future, even during times of stress (e.g. prolonged

drought).

Fair The natural resource is in a state that does not meet some environmental, economic and social

expectations, based on this indicator. Thus, desirable function cannot be expected from many

processes/services expected of this resource, now and into the future, particularly during times of

stress (e.g. prolonged drought).

Poor The natural resource is in a state that does not meet most environmental, economic and social

expectations, based on this indicator. Thus, desirable function cannot be expected from most

processes/services expected of this resource, now and into the future, particularly during times of

stress (e.g. prolonged drought).

Unknown Data are not available to determine the state of this natural resource, based on this indicator

Not applicable This indicator of the natural resource does not lend itself to being classified into one of the above

condition classes

2.3.3 Reliability

The reliability of the information used in the report card is rated based on the average of subjective scores (1

[worst] to 5 [best]) given for information currency, applicability, level of spatial representation and accuracy.

Definitions guiding the application of these scores are provided in Table 2.3 for currency, Table 2.4 for

applicability, Table 2.5 for spatial representation and Table 2.6 for accuracy.

Table 2.2. Guides for applying information currency

Currency score Criteria

1 Most recent information >10 years old

2 Most recent information up to 10 years old




Table 2.3. Guides for applying information applicability

Applicability score Criteria

1 Data are based on expert opinion of the measure

2 All data based on indirect indicators of the measure

3 Most data based on indirect indicators of the measure

4 Most data based on direct indicators of the measure

5 All data based on direct indicators of the measure


Table 2.4. Guides for applying spatial representation of information (sampling design)

Spatial score Criteria

1 From an area that represents less than 5% the spatial distribution of the asset

within the region/state or spatial representation unknown

2 From an area that represents less than 25% the spatial distribution of the asset

within the region/state

3 From an area that represents less than half the spatial distribution of the asset

within the region/state

4 From across the whole region/state (or whole distribution of asset within the

region/state) using a sampling design that is not stratified

5 From across the whole region/state (or whole distribution of asset within the

region/state) using a stratified sampling design

Table 2.5. Guides for applying accuracy information

Reliability Criteria

1 Better than could be expected by chance

2 > 60% better than could be expected by chance

3 > 70 % better than could be expected by chance




3 Results

3.1 Trends in annual accumulated FFDI

Figure 3.1 presents the spatial variation in the trends in annual accumulated FFDI, interpolated from weather

monitoring stations distributed across SA for the time period 1978 – 2019 (provided by Bureau of Meteorology,

based on Dowdy, 2018).

Figure 3.1. Trend in annual accumulated FFDI per decade 1978 – 2019


3.2 December accumulated FFDI 1950 – 2019

Figure 3.2 presents the total accumulated FFDI for December for each year from 1950 to 2019 (provided by

Bureau of Meteorology, based on Dowdy, 2018).

Figure 3.2. December accumulated FFDI for the years 1950 – 2019

3.3 Analysis of Trend, Condition and Information Reliability

3.3.1 Trend

The trend rating for fire danger weather was determined to be ‘getting worse’ (Table 2.1). A trend of increase in

annual accumulated FFDI has been observed over much of South Australia over the past 42 years. A small part of

the north eastern edge of the state has no observed trend, however the rest of the state shows an increasing

trend, with the greatest increase occurring in the east and mid-north of the state.


3.3.2 Condition

The Condition rating assigned is ‘poor’ because, through 2018 to 2019, the persistence of below average rainfall

led to increasingly high FFDI values across much of SA. During December 2019 into early January 2020 hot

conditions combined with a dry landscape and strong winds to produce particularly dangerous fire weather

conditions. In December 2019, the area-averaged accumulated FFDI values for SA were the highest for any

December since records began in 1950. This was 24 percent higher than the previous highest December on

record in 1972. This aligns with the condition definition of ‘poor’ (Table 2.2), i.e. “the natural resource is in a state

that does not meet some environmental, economic and social expectations, based on this indicator. Thus,

desirable function cannot be expected from many processes/services expected of this resource, now and into the

future, particularly during times of stress (e.g. prolonged drought)”.

3.3.3 Reliability

The reliability of the information used in the report card is rated based on the average of subjective scores (1

[worst] to 5 [best]) given for information currency, applicability, level of spatial representation and accuracy.

Definitions guiding the application of these scores are provided in Table 2.3 for currency, Table 2.4 for

applicability, Table 2.5 for spatial representation and Table 2.6 for accuracy. The overall reliability rating for this

report card is ‘good’. This is the rating ascribed to an overall score of 3 (out of a maximum of 5), based on the

average of the ratings ascribed to applicability, currency and spatial representation of the information (Table 3.1.

Information reliability scores

A reliability rating of ‘good’ has been assigned to the information in the Climate: Fire danger weather report

card.

The information has a currency score of 5 as measured FFDI data up to 2019 has been used in the map of the

annual FFDI trend and the graph of accumulated December FFDI.

The information has an applicability rating score of 3 because the FFDI data is based on weather measurements

that are direct indicators of the weather variables used in the calculation of FFDI, however the measure of

accumulated FFDI uses only the FFDI rating at a particular time each day and hence does not represent the FFDI

at all times.

A spatial representation score of 3 has been assigned because the data is from weather stations that are

distributed throughout the area of the state, however, each one is representative of weather conditions over a

limited area within the vicinity of the station. Hence, the whole extent of the state is represented by the weather

station network, however the measurements represent less than half the spatial variation of the weather

conditions within the state.

The accuracy of the data, for the purpose of the report card, has been ascribed a score of 3. The FFDI figures are

calculated from direct measurements of weather variables at calibrated rainfall gauging stations distributed

across South Australia. However, the coverage of these gauging stations is variable across the state, with the

more remote areas having a sparse distribution of stations. Furthermore, the measure of accumulated FFDI uses

only the FFDI rating at a particular time each day and hence does not represent the FFDI at all times.

The overall reliability score for this report card is 3.75 (rounded to 4), based on Table 2.8Table 3.1. Information

reliability scores .

Table 3.1. Information reliability scores for FFDI

Indicator Applicability Currency Spatial Accuracy Reliability

FFDI data 3 5 3 3 3.75



4 Discussion

4.1 Trend

The overall risk of bushfires and grass fires is driven by a range of factors, including the vulnerability of people

and assets, weather, fuel availability and dryness, ignition sources, and the viability of fire suppression measures.

However, the likelihood of fires starting and spreading is strongly affected by weather conditions. The Forest

Fire Danger Index (FFDI) reflects longer-term rainfall and temperature patterns and shorter-term weather.

Daily FFDI values are summed over longer periods of time to determine the accumulated FFDI. The observed

increase in FFDI has been variable across the state. The far north-west has seen the lowest increases. The highest

rates of increase in FFDI (and corresponding Grass Fire Danger Index) are observed in the mid north, south east

and far north east. The 2020 report card Fire Danger Weather assessment uses FFDI values calculated from

observed weather data from BOM monitoring stations distributed across South Australia.

The observed changes in the occurrence of severe and extreme fire weather increase the likelihood of bushfires

impacting lives, property and the environment in South Australia. Climate model projections indicate increasing

temperatures and declining rainfall in parts of SA due to higher concentrations of atmospheric greenhouse

gases.

4.2 Condition

Low rainfall and high temperatures have exacerbated spring and summer fire weather conditions in recent years.

Through 2018 to 2019, the persistence of below average rainfall led to increasingly high FFDI values across much

of SA. During December 2019 into early January 2020 hot conditions combined with a dry landscape and strong

winds to produce particularly dangerous fire weather conditions. In December 2019, the area-averaged

accumulated FFDI values for SA were the highest for any December since records began in 1950. This was 24

percent higher than the previous highest December on record in 1972.

State agencies, including the CFS and the Department for Environment and Water, contribute to a range of

measures to manage and reduce the overall risk of bushfires, including the management of fuel loads, fire

suppression, and planning regulations for areas of high risk.

Following the widespread fires of 2019/20, the SA Government commissioned an independent review to assist in

planning for future fire seasons. This was supported by the SA Fire and Emergency Services Commission and

experts from across the emergency services sector.


5 References

Bureau of Meteorology (BoM) 2019(a), Special Climate Statement 71—severe fire weather conditions in southeast

Queensland and northeast New South Wales in September 2019, 24 September 2019,

http://www.bom.gov.au/climate/current/statements/scs71.pdf (viewed 16/10/2020)

Bureau of Meteorology (BoM) 2019(b), Special Climate Statement 72—dangerous bushfire weather in spring 2019,

18 December 2019, http://www.bom.gov.au/climate/current/statements/scs72.pdf (viewed 16/10/2020)

Bureau of Meteorology (BoM) 2020, Special Climate Statement 73—extreme heat and fire weather in December

2019 and January 2020, 17 March 2020, http://www.bom.gov.au/climate/current/statements/scs73.pdf (viewed

16/10/2020)

Dowdy, A. J. (2018). Climatological variability of fire weather in Australia. Journal of Applied Meteorology and

Climatology, 57(2), 221–234. https://doi.org/10.1175/JAMC-D-17-0167.1

Noble I.R., Gill A.M., Bary G.A.V. (1980), McArthur’s fire-danger meters expressed as equations. Australian Journal

of Ecology 5:201–203

http://www.bom.gov.au/climate/current/statements/scs71.pdf



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Technical information supporting the 2020 climate (fire